Moderate hypoglycaemia obliterates working memory in humans with and without insulin treated diabetes
- 1Department of Psychology, University of Edinburgh, 7 George Square, Edinburgh EH8 9JZ, Scotland, UK
- 2Department of Diabetes, Royal Infirmary of Edinburgh
- Correspondence to: Professor Ian J Deary; i.deary{at}ed.ac.uk
Moderate hypoglycaemia is common in people with insulin treated diabetes, and some mental functions deteriorate during this state. Working memory is a crucial cognitive process, necessary for many everyday tasks, but its integrity during hypoglycaemia is not known. We examined the effect of moderate hypoglycaemia on working memory in 32 young adults (16 with type 1 (insulin dependent) diabetes). Mean performance on working memory was reduced almost to levels of chance. During hypoglycaemia, therefore, this important mental ability is almost obliterated though the subjects remain fully conscious.
Working memory is the mental capacity simultaneously to store and manipulate information.1 It supports human capabilities in composing spoken language and in negotiating the environment. Individual differences in working memory correlate very highly with measures of reasoning and general intelligence.2 Glucose is the brain’s principal fuel, and mental function deteriorates when arterial plasma glucose falls below 3.0 mmol/l. Mental functions that are complex and performed under time pressure are particularly affected, the usual finding being a modest reduction in performance.3 To date, working memory has not been studied during hypoglycaemia. Here we examine the effect of controlled, moderate hypoglycaemia on performance of a challenging working memory task.
Working memory performance was studied in 32 young adults. Sixteen (nine men, seven women) were healthy, non-diabetic subjects aged between 26 and 34 years …
